Covance: Increased interest in method harmonization
Covance said to ensure safety and regulatory compliance clients require testing in a variety of samples that differ in complexity and range from fresh produce to concentrated botanical extracts.
The firm tests infant formula, finished food and beverages, supplements and ingredients.
Lukas Vaclavik, of Covance, said to meet client requirements in food contaminant and residue testing, instrumentation such as mass spectrometry and hyphenated techniques need to be used.
Analysis type and examples
Vaclavik said it uses the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) workflow for sample preparation in pesticide residue analysis.
“Additionally, QuEChERS extracts are compatible with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) techniques, therefore can be used for extraction of both LC- and GC-amenable pesticides,” he told FoodQualityNews.
“This is needed to cover the majority of pesticides that must be monitored to ensure legislative compliance. Another advantage is availability of additional clean-up options based on solid phase extraction that give flexibility when dealing with test samples of varying complexity.”
GC-MS/MS is frequently used when it comes to analysis of nutrients and food contaminants as well as pesticide residues, said Vaclavik.
“GC-MS/MS is suitable for analysis of slightly non-polar and volatile compounds and provides high sensitivity and selectivity, especially when operated in MRM (multiple reaction monitoring) mode. MRM is a data acquisition mode typically used with triple quadrupole or ion trap mass spectrometers,” he said.
“It is based on isolation of analyte ions, their fragmentation and monitoring of multiple suitable product ions. MRM is particularly useful when analysing target compounds present at low concentration in complex samples.”
Vaclavik said methods allowing analysis of multiple compounds of interest reduce time and costs associated with compound determination.
“Modern workflows based on LC/MS and GC/MS techniques can quantify hundreds (triple quadruple and ion trap instruments) or even more than a thousand of analytes (time-of-flight or orbitrap instruments) in a single run,” he said.
“The number of analytes that can be simultaneously detected by a mass spectrometer is dictated by speed of instrument electronics, so the ‘ceiling’ is largely dependent on the progress in this field.”
Prior to using any method in routine analysis, the firm performs a method validation to make sure it generates accurate and repeatable results in all sample types of interest.
“In routine testing quality, control measures such as blank samples fortified with target analytes at reporting limit are taken with each batch of test samples,” said Vaclavik.
“Maintenance and suitability checks are performed to ensure instruments are capable of detecting low enough analyte concentrations and provide satisfactory chromatographic separation etc. Last but not least, all our laboratories take part in relevant proficiency testing schemes to make sure our methods generate unbiased results.”
Covance has labs in Anaheim, California; Battle Creek, Michigan; Greenfield, Indiana; Ithaca, New York; Livermore, California; Madison, Wisconsin and Naples, Florida.
It also has a various locations in Europe and the Asia Pacific region including a nutritional chemistry and food safety lab in Harrogate, UK.
LabCorp acquired Covance for an equity value of $6.2bn in 2015.
High throughput demands
In the high-throughput environment of a commercial food testing laboratory, Vaclavik said it is essential to continuously look for cost and time-saving improvements.
“For example, we recently evaluated a new triple quadrupole GC/MS system in pesticide residue analysis. This new system provides improved sensitivity and can therefore be operated with lower sample introduction compared to older, less sensitive instruments,” he said.
“We found that use of lower injection volume results in considerable reduction of instrument maintenance frequency and increased column lifetime, as well as improved quality of the data during analysis of difficult complex samples. We plan to upgrade our GC/MS systems installed in our laboratories during 2017.”
One approach to increase sample throughput being evaluated for LC-MS analyses of B vitamins is based on allowing delivery of two parallel chromatographic separations to a single triple quadrupole mass spectrometer.
“This configuration allows for 2-fold increased sample throughput,” said Vaclavik.
“We also plan to start using this approach for other high sample volume assays, including contaminant and residue testing, in the near future and eventually increase the number of LC systems to further boost up the sample throughput.”
After the criminal blackmail threats to New Zealand dairy producers, Covance and clients set up and validated an LC-MS/MS method for testing the compound 1080 (sodium fluoroacetate) in US, European and Singapore labs.
“The method needed to be available in an extremely short period of time, so the method development, troubleshooting and validation work was performed 24/7 by taking advantage of our global presence," said Vaclavik.
“Successful cross-site validation was followed by high sample volume testing to ensure clients’ products are free of this poisonous chemical.”
